The wiring for the electrical systems of aircraft is conventionally assembled outside the aircraft into wire harnesses that include large numbers of wire segments having opposite ends leading to various connectors. The number of wire segments in a single harness can be as large as several hundred. The manufacture of a wire harness is complicated and difficult to automate and, thus, is generally highly labor intensive. One of the major procedures in the manufacture of a harness is the processing of the ends of the wire segments. Such processing is commonly called "termination" and includes, but is not limited to, stripping insulation from the ends of the segments and installing electrical contacts and/or lugs on such ends.
One approach to increasing the efficiency of the manufacture of wire harnesses is to automate the processing of the wire segment ends. Known systems incorporating this approach have the problems of being relatively inflexible, retaining major inefficiencies, and being subject to frequent system shutdowns. One of the major reasons for these problems is that the individual wire segments are moved through the system and processed in a predetermined sequence. Thus, at any given point, the rate of movement of the segments through the system is governed by the segment end processing procedure or other procedure which has the longest completion time. In addition, such systems are vulnerable to total system shutdowns caused by a fault in any single one of a number of specific processing devices.
Systems for manufacturing electrical harnesses are disclosed in U.S. Pat. No. 3,766,624, granted Oct. 23, 1973, to R. K. Grebe et al.; U.S. Pat. No. 4,638,558, granted Jan. 27, 1987, to H. L. Eaton; U.S. Pat. No. 4,653,159, granted Mar. 31, 1987, to J. A. Henderson et al.; and U.S. Pat. No. 4,653,160, granted Mar. 31, 1987, to F. Thorkildsen et al. In the system disclosed in each of these patents, work stations are lined up along a conveyor. Individual wire segments are mounted on the conveyor which moves intermittently to allow the segments to be processed at the work stations. Wire harness manufacturing systems in which the wire ends are processed after the wire is laid out are disclosed in U.S. Pat. No. 3,842,496, granted Oct. 22, 1974, to P. W. Mercer; and U.S. Pat. No. 4,433,479, granted Feb. 28, 1984, to Y. Suzuki et al.
A system for manufacturing wire harnesses for aircraft in which the segments are moved sequentially through the system is disclosed in U.S. Pat. No. 4,520,966, granted Jun. 4, 1985, to J. T. Bloch and the present applicant; U.S. Pat. No. 4,677,734, granted Jul. 7, 1987, to the same inventors; and U.S. Pat. No. 4,803,778; granted Feb. 14, 1989, to the present inventor. In the system, individual wire segments are loaded into canisters and placed on a rotatable table. A robot swivels to pick up a canister, swivels to an equipment rack on which a plurality of termination devices are mounted, and then deposits the canister with the processed segment in a bay of a queuing subsystem for the lay-up phase of the manufacture.